Tuning device



l Sept. l5, 1942. B. A. scHwARz Erm. I 2,296,060

` TUNING DEVICE Filed Jan. 6, 1940 2 Sheets-Sheet l Sept. 15, 1942, B. A. SCHWARZ Em 2,296,060

TUNING DEVICE Filed Jan. 6, 1940 2 Sheets-Sheet 2 attorneys Patente-d Sept. 15, 1942 Bertram A. Schwarz and James G. Funk, Kokomo, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 6, 1940, Serial No. 312,680

7 Claims.

The present invention relates to a radio tuning mechanism and more particularly concerns manually and automatically controlled poweroperated indexing means for controlling the tuning mechanism.

In prior mechanisms of the above type a reversible electric motor was usually provided for actuating the indexing means., In some mechanisms the motorwas directly connected to the indexing means and control means was provided to reverse and stop rotation of the motor in a given angular position by mechanical and electric control means, both of which were manually and automatically actuated. In other mechanisms the motor was connected to the indexing means by a clutch which was disengaged and the motor deenergized after the tuning mechanism had been rotated by the motor in either direction to a given angular position. The controls for either of these two types of mechanisms were complicated and required mechanical and electrical interlocks which were expensive and subject to failure.

In the present invention the tuning mechanism is actuated by spring-operated indexing means, and non-reversible power-actuated means is provided to tension the spring means and limit th'e rate of movement of the springoperated indexing means. The control means for both the spring-operated and power-actuated means is simplified as no reversing control is required and no control means is necessary to stop operation of the power-operated means in a definite angular position. This constitutes the principal object of our invention.

The means by which this and other associated objectsare accomplished is described in the following speciiication and illustrated in the accompanying drawings, in which:

Figure 1 is a top plan view of the tuning mechanism in which automatic indexing means is included;

Figure 2 is a side elevation of the mechanism with some of the parts broken away and others shown in section to show details thereof;

Figure 3 is a Ydiagrammatic View showing manually and automatically actuated electrical control devices and the circuit connections extending therebetween to control the spring-operated indexing means and power-actuated means;

Figure 4 is a side elevation of the mechanism with some of the parts broken away and others shown in section to shoW details of a power-actuated means of slightly different form.

Referring to the drawings, represents a housing which encloses the tuning mechanism and means for controlling the mechanism. The housing I may also enclose a radio receiver, not shown, having a tuning device, by which the receiver may be tuned by means of a shaft 3 capable of being rotated to different angular positions.

Conventional manual tuning means may be provided for rotating a control shaft 3 to tune the receiver such as a shaft 5 having a worm 'l fixed thereon, the shaft 5 being mounted in any convenient manner so that it may be moved to bring the worm 'I into mesh with the worm wheel 9 fixed to shaft 3, as shown, in order to rotate it or prevent rotation thereof. Movement of the shaft 5 so that the Worm 'I is moved out of mesh with the worm wheel 9 permits independent rotation of the Worm wheel 9 and shaft 3.

Spring-operated indexing means and poweroperated means for controlling the rate of movement and the tensioning thereof are also provided to rotate a gear I3 in either direction to any one of a plurality of preselected angular positions by merely depressing a push button. The gear I3 meshes with a gear I5 also fixed to the control shaft 3 to tune the receiver automatically. The spring-operated and power-actuated means are supported in a hollow cast frame indicated generally at Il. The gear I3 actuated by these means is fixed on the end of a shaft Il rotatably supported in aligned openings I9 in the Vertical end anges 2| of the frame II. A plurality of pinions `23 are axially spaced on the shaft I1 by sleeves 25 located therebetween. Each pinion is mounted for angular adjustment on the shaft AIl and any well-known means for connecting the pinions for rotation with the shaft may be used,ksuch as that shown in our Patent No. 2,258,814.` The particular means by which the pinions may be connected to the shaft Il for rotation therewith after having been angularly adjusted with respect thereto forms no` part of the present invention.

vertically spaced rack bars indicated at 21 mesh with each pinion on either side thereof and are slidably mounted in vertically aligned grooves 29 in the upper and lower horizontal flanges 3| and 33 of the frame I, which are located, respectively, above and below the pinions. The rack bars above and below each pinion meshing therewith are moved transversely in opposite directions when the pinions 23 are connected to the shaft II and this shaft is rotated by control shaft 3 which is operatively connected thereto and is actuated by the manual tuning means described. Either rack bar 21 of a pair meshing with an individual pinion is contacted and moved by a plate 35, which is also slidably mounted in the vertically spaced grooves 29, and is urged into contact with the ends of either of the racks by helical tension springs 31 attached to the plates at 39 and to the frame i i by brackets 4| fixed to the upper and lower frame anges 3| and 33. As best shown in Figure 2, when the plate 35 is moved inwardly in the grooves 29 by the springs 31 it will contact and move the upper rack bar 21 inwardly and rotate the pinion 23 and shaft I1 counter-clockwise, and, conversely, inward movement of the lower rack bar by the plate 35 causes clockwise rotation of the pinion 23 and shaft I1. When the ends of both rack bars are moved into vertical alignment the plate 35 will contact both bars simultaneously and further inward movement of the plate will cease and movement of the racks and pinion will also cease. The pinion will accordingly be rotated in either direction to a denite angular position as will the shafts |1 and 3 when any plate 35 is moved inward by the spring 31 to its fullest extent.

Power-actuated means is p-rovided for simultaneously moving all the plates 35 outwardly away from the racks to tension the springs 31 and to also limit the rate of inward movement of any of these plates by the spring 31. This means comprises an electric motor 43 fixed to the lower frame flange 33 and having a pinion i5 rotated by the motor which meshes with a gear l1 xed on the lower end of a vertical shaft i9 rotatably mounted in an opening 5| in the frame flange 33. A worm 53 on the upper end of the shaft 49 meshes with a worm wheel 55 xed on a horizontal shaft 51 rotatably supported in aligned openings 59 in the frame end flanges 2 As shown in Figures 1 and 2, a crank arm 59 is xed on one end of the shaft 51 and a crank disc 6| is xed on the other end. A cam slot E3 and a cam projection 95 angularly spaced from the slot are provided on the periphery of the crank disc 6|. A pair of connecting rods 51 are pivotally connected respectively to the crank arm `and crank disc and the opposite ends of these rods are also pivotally attached to a bar 58 supported for reciprocating movement in horizontal slots 69 in the frame end flanges 2|. A manually operable switch indicated at 9| and a 'switch indicated at |l3, to be described later, serve to start and stop rotation of the motor 43 which causes the shaft 51 t0 be rotated clockwise as viewed in Figures 2 and 3. rThe shaft 51 is normally stopped so that the rod 68, connecting rods E1, and crank disc 9| occupy the positions shown in the above figures, but the shaft 51 may be stopped when the rod 58 has been moved inward by the connecting rods 61 toward the shaft 51 to its maximum inward position. When the shaft 51 is stopped in this position the connecting rods 61 are in a horizontal dead center position and the cam projection 65 on the crank disc 6| is in the top dead center position. Movement of the rod 68 outward or away from the shaft 51 by the motor 43 moves all the plates 95 outward to tension the springs 31 as the rod S8 extends through horizontal slots 35 in the inner face of each of these plates and exerts outward force on the bottom of the slots. Movement of the rod 68 inward toward the shaft 51 by the motor limits the rate of movement of any of the plates 35 which are held in contact with the rod 58 by the springs 31.

rIhe force exerted by the springs on the plat acting through the connecting rods cannot cause rotation of the shaft 51 on account of the irreversible characteristics of the gear train connecting the shaft 51 to the motor.

A modied structure for moving the plates outward and controlling the rate of inward movement thereof is shown in Figure 4. This structure consists of a plurality 0f cams 10 fixed on the shaft 51 for operating plates 35a which also have springs 31 attached thereto tending to urge the inner edge of the plates into contact with individual cams 19 which control the reciprocating movement of the plates 35a which operate rack bars 21 in the same manner as described previously. The cams may be of different contour from that shown so that any desired rate of movement of the plates 35a in either direction may be obtained when the cams 10 are rotated by the motor 43. The toe of the cams 10 shown in Figure 4 is on the horizontal center line of the shaft 51 but is rotated clockwise through a small angle from this position when the motor is stopped with the cam slot 63 in the top dead center position as shown in Figure 3, and when the cam projection 65 is in the top dead center position the toe of the cam 15 is rotated 180 degrees clockwise from the position shown in Figure 4.

A plurality of manually releasable latches indicated at 1| are provided to retain each of the individual plates 35 or 35a in substantially their maximum outward position when moved to this position by either the rod 63 or the cams 10 respectively. The rod y|58 and the cams 19 may be moved out of contact with the plates 35 or 35a when they are in the latched position, if desired, by causing the motor 4.3 to be stopped so that the shaft 51 is rotated through a slight angle beyond the position where the plates were engaged by the latches. The latches 1| are pivoted on a bar 12 extending transversely to the path of movement of the plates. The ends of the bar 12 are fixed in any convenient manner to the housing Each latch 1| has an inwardly projecting arm 13 having a beveled end 14 and a notch 15 adjacent thereto which engages a lug 16 integral with each plate when the plate is moved to approximately its maximum outward position. Downwardly projecting arms 11 on each of the latches 1| are normally held in contact with the inner ends of individual push buttons 19 slidably mounted in an opening 8| in the vertical flange 33 of the housing I by a rod 85 having an insu lated sleeve B1 mounted on the rod intermediate the ends thereof and bearing on the inner sides of all the arms 11. The rod has cranked end portions 89 bent around the bar 12 and is moved angularly with respect thereto by any latch 1| when its respective push button is depressed to release the plate held by this latch.

An electric control switch indicated at 9| is associated with the rod 85 to control energization of the motor to cause it to rotate when any latch 1| is released. This switch has three parallel spring contact bladesv 93, and 91, the lower ends of which are embedded in an insulated base member 99 fixed to the vertical flange 83 of the housing The central blade 95 f this switch is longer than the other blades and extends upward inside of the bar 85 and is stressed s0 that its upper end normally bears on the insulated sleeve 81 to urge it outward into contact-I with all the arms 11 of the latches to project all the push buttons 19 and hold all the notches 15 in the arms 13 of the latches inengagement with the lugs 16 of the plates 35 or 35a as shown in Figures 1, 2 and 4. The blade 95 also bears on the blade 91 when in this normal position and is out of contact with the blade 93 on the opposite side thereof. An insulated stop member is suitably supported on the housing I in spaced relation to the blade 95 to limit inward movement of it and also the push buttons 19.

The switch |03 previously referred to is electrically connected to the switch 9i and both of these switches serve to maintain current flow to the-motor 43 or to interrupt the ycurrent ilow thereto. The switch |03 is best shown in Figure 3 and comprises five parallel spring contact blades |05, |01, |09, I|I and H3, embedded in an insulated base member I 04 which is fixed in any suitable manner to the frame Vend flange 2| adjacent the crank disc 6|, as best shown in Figure 1. The blade I I is longer than the other blades and has a downwardly bent end I l 2 which normally bears on and follows the periphery of the cam disc 5|. The blade I I I occupies the position shown in Figure 3 when the motor is deenergized after tensioning the springs 31 and moving the plates to their latched position. The end ,II2 of this blade is shown in contact with the bottom of the cam slot 53 and the central portion thereof bears on the end of the blade II3, which exerts upward pressure on the blade III. When the crank disc is rotated clockwise from the position shown, the end I i2 of the blade III is moved upward onto the periphery of the disc BI by the beveled portion of the slot t9 and the blade III is moved out of contact with the blade ||3 slightly after it is moved into contact with the end of the blade |91 bending this blade upwardly a slight amount. The blade |99 located'below the blade |01 has its end normally in contact with the blade |91 and normally exerts a slight upward force thereon so that when the blade |01 is moved upward slightly by the blade III the blade |09 remains in contact with the blade |01. When the cam projection 55 having a beveled edge 56 contacts the end I l2 of the blade III the blade III is moved upward a greater amount, which, accordingly, moves the blade |01upwardly a corresponding amount and causes it to" move into contact with the blade above it slightly before it breaks contact with the blade |09 below it. When the cam projection is directly under the end II2 of the blade III the shaft 51 has been rotated to a position so that any plate 35 or 35a which has been released by its respective latch 1I is limited by either the crank arm 09 and crank disc 6| or its respective cam to its maximum inward position. When the cam 'projection 65 is rotated out from under the end II2 of the blade III the blade III will move down to its original position, causing the blade |01 to move down with the blade |09 slightly before it breaks contact with the blade |05. The end II2 willfollow the arcuate periphery of the disc until the disc has been rotated a full revolution by the motor, where it will again enter thecam slot 63 and move the blades o-f the switch |93 to their normal position as shown in Figure 3. The blade I II may be grounded, as indicated at I2I, to the cast frame II, the blade I|3 is connected to the blade 93 of the switch 9| by a conductor I I5, the blade |05 is connected by a conductor ||1 to the blade 91 of the switch 9| and the blade |99 is connected to the central blade 95 of the switch 9| by a conductor |19, Both the switches 9| and |93 control energization and deenergization of the motor winding indicated at M from a battery |23 connected thereto by a conductor |25. The opposite side of the battery is connected to the conductor I|9 by a lead |21 and the other side of the motor Winding is also grounded to the frame II and indicated at |29.

Setting operation In order to set any spring-operated indexing means so that the control shaft 3 will be moved to a preselected angular position when the push button controlling this means is depressed, the following procedure is followed:

The pinions are released from the shaft and the receiver is tuned to the particular broadcast station desired by rotating the shaft 5, which rotates the control shaft 3 and adjusts the tuning device of the receiver. Rotation of the shaft 3 also causes the shaft I1 to be rotated to a corresponding angular position. The shaft 3 is then held in this position and any one of the push buttons 1.9 is depressed and held depressed, which moves its respective latch 1I to release the push plate 35 and allows it to contact the rod 60 and at the same time moves the blade of the switch 9| into contact with the blade 93. When these blades are in contact the motor winding M is energized from the battery |23 through the conductors |21 and |29, through the blades 93 and 95 of switch 9|, conductor I|5 and to ground at I2I through blades II3 and III of the switch |03. One side of the motor winding M is also grounded to the frame II at |29 and the other side is connected to the battery |23 by the conductor |25 and a circuit is thus completed through the frame II which causes the motor to rotate the shaft 51 and crank disc 6| clockwise, which controls the rate of inward movement of the plate 35. Initial rotation of the crank disc moves the blade I Il upward into contact with the blade |01 to establish a holding circuit and then moves out of contact with the blade II3. The holding circuit comprises the conductors |21 and I I9, blades |09, |01, II| of the switch to ground at 12|. The motor continues to revolve the disc until the cam projection 65 moves the blade III upward, causing the blade |01 to move into contact with the blade |95 and then move out of contact with the blade |09, thus breaking the holding circuit through the blades |09 and III to ground at I2I and stopping the motor and the cam disc in this position. It will be evident that as long as the push button is held depressed vthe blades 95 and 93 of the switch 9| will remain in contact and the blades III, |01, |05 of the switch |03 will likewise be held in contact as long as the cam projection is under the end H2 of the blade III. Thus the circuit through the grounded portion of the holding circuit is broken as the switch I I I, which is grounded at I2I, is now only in contact with the blades |01 and |95, the latter of which can only be connected to the battery by the conductor ||1 and switch blades 91 and 95 of the switch 9|, and these blades are separated when the push button is held depressed. The motor will remain stopped as long as this button is held depressed, and as the shaft 51 has now been y revolved sufficiently to allow the Plate to contact and move the racks Z1 so that their ends are in vertical alignment, thus stopping movement of the plate in its innermost position, the pinion 23 manually tuned to the desired broadcast station. With the pinion, racks and plate held in this position it is only necessary to connect the pinion to the shaft I1 for rotation therewith and release the push button which allows the blade 95 of the switch 9| to move into contact with the blade 91. The motor will then be energized through the conductor 27, l i9, blades 95 and 9T of the switch 9|, conductor Ill and to ground at 2l through the blades |65, |01 and I l l. The motor will start and rotate the crank disc l clockwise to cause initial outward movement of the plates and when the cam projection 65 moves out from under the end H2 of the blade HI the motor will again be energized through the above holding circuit connections and continue to rotate and move the plate outward to its latched position and nally stop when the end H2 of the blade III enters the cam depression 63, opening the holding circuit. All the other indexing means are set in like manner.

With all the indexing means set as described above, the shaft 3 will be rotated to a preselected angular position; in order to tune the radio receiver to a particular broadcast station any one push button is depressed for a short time and then released. Depression of the push button releases a spring-actuated plate and energizes the motor to start rotation of the crank disc which operates the switch |63 to establish the holding circuit and the push button can then be released. The motor will operate until the crank disc has been revolved a full revolution as a circuit is established through the blades 95 and Sl of the switch H when the push button is released 'to energize the motor during the time the blades of the switch ID3 are positioned by the cam projection to break the holding circuit through this switch. A full revolution of the shaft 5l controls both the rate of movement of the plate to index the shaft 3 and movement of the plate back to its latched position to tension the springs for subsequent identical operation when released by its respective push button.

The position at which the shaft 5l is stopped after the plate or plates have been moved or their latched position is not critical and may be varied to tension the springs to greater or less extent and the latching means may be operated remotely instead of directly as shown. The structure shown in Figure 4 in which cams 'l0 are used to control movement of the plates 35a operates in the same manner as described, as the cams and plates are the only difference between the two forms of structure shown. Either form of structure shown and `described provides a spring-operated non-reversible power-operated means requiring a simple control apparatus and little manual eiort and attention in order to obtain any one of a plurality of broadcast stations by merely depressing a particular push button. The cam structure oers a convenient means for varying the rate of inward or outward movement of the plates.

We claim:

l. In a tuning mechanism for a radio receiver means, and combined manual and automatic controls for starting operation of said poweractuated means to initially control the rate of movement of said actuating means by said resilient means and to nnally stop operation of said power-actuated means after said actuating means has been moved by said power-actuated means to tension said relisient means.

2. In a tuning mechanism for a radio receiver comprising a tuning device capable of angular adjustment, indexing means for adjusting said tuning device to a predetermined angular position, actuating means for said indexing means, resilient means operatively connected to said actuating means, power-actuated means operatively connected to said actuating means to tension said resilient means and to control the rate of movement of said actuatingmeans by said resilient means, manually releasable means for engaging and preventing movement of said actuating means by said resilient means and control means operated by both said last named means and said power-actuated means to initially permit movement of said actuating means by said resilient means at a rate controlled by said power-actuated means, and nally stop operation of said poweractuated means after said actuating means is again reengaged by said manually releasable means.

3. In a tuning mechanism for a radio receiver comprising a tuning device capable of angular adjustmentJ a plurality of indexing means for adjusting the tuning device to any one of a plurality of predetermined angular positions, actuating means for each of the indexing means, resilient means operatively connected to each actuating means, power-actuated means operatively connected to each actuating means for moving all of said actuating means to tension all of said resilient means, a plurality of manually releasable latches, each of which is arranged to engage and hold a respective actuating means against the force of its respective resilient means, and control means for said power-actuated means comprising a control element movable by any one of said latches upon release of same to initiate operation of said power-actuated means and a second control element movable by said power-actuated means to stop operation thereof after any one of said actuating means has been reengaged by its respective latch.

4. In a tuning mechanism for a radio receiver comprising a tuning device, a plurality of indexing means for adjusting the tuning device to any one of a plurality of predetermined angular positions, actuating means for each indexing means, resilient means operatively connected to each actuating means, power-actuated means for moving all of said actuating means to stress all of said resilient means and to control the rate of movement of any one or all of said actuating means by said stressed resilient means, a plurality of manually releasable latches, each of which is arranged to engage and hold a respective actuating means against the force of its respective stressed resilient means, and control means comprising an element movable by any latch upon the release thereof to start operation of said power-actuated means, and a second control element movable by said power-actuated means to stop operation thereof after any one of said actuating means has been reengaged by its respective latch.

5. In a tuning mechanism for a radio receiver comprising a tuning device capable of adjustment, a plurality of indexing means for adjusting the tuning device to any one of a plurality of predetermined positions, actuating means for each indexing means, resilient means operatively connected to each actuating means, means for moving all of said actuating means lto stress said resilient means and for controlling the rate of movement of any one of said actuating means by said resilient means whereby the indexing means actuated thereby will be moved to a predeter- 1 mined position, an electric motor for driving said last named means, a plurality of manually releasable latches, each of which is arranged to engage and hold a respective actuating means against the' force of its stressed resilient means,

a source of currenty means for connecting said motor to said source of current and for disconnecting said motor from said source, said last named means including a control switch operatively connected to and movable by any one of said latches, a cam-operated switch operatively connected to and driven by said motor, and a plurality of conductors interconnecting said switches whereby said motor is energized upon the release of any latch and deenergized by said cam switch, either upon completion oi the movement of any indexing means to a predetermined position by its respective actuating means and resilient means, or after any actuating means has been moved to its latched position to stress its respective resilient means.

6. In a tuning mechanism for a radio receiver comprising a tuning device capable of adjustment, a plurality of indexing means for adjusting the tuning device to any one of a plurality of predetermined positions, actuating means for each indexing means, resilient means operatively connected to each actuating means, power-actuated means for simultaneously moving all of said on said actuating means by said resilient means and for limiting the rate of movement of any one of said actuating means by said resilient means to move any one of said indexing means to a predetermined position, said last named means comprising a rotatable shaft and a plurality of cams xed thereto on each of which an individual actuating means is normally urged into sliding contact therewith 4by its respective resilient means, a manually releasable latch arranged adjacent each of said actuating means normally engaging and holding each of said actuating means against the action of said resilient means and control means for starting and stopping operation of said power-actuated means, said control means including a control element actuated upon the release of any latch to supply power to said power-actuated means and a second control element actuated by said power-actuated means to cut off the power supplied to said power-actuated means after any actuating means released by its latch is again engaged thereby.

7. In a tuning mechanism for a radio receiver comprising a tuning device capable of adjustment, a plurality of indexing means for adjusting the tuning device to any one of a plurality of predetermined positions, resilient means operatively connected to each actuating means, power-actuated means for simultaneously moving one or all of said actuating means to stress all of said resilient means and for limiting the rate of movement of any one actuating means by said resilient means to a predetermined position, said last named means comprising a rotatable crankshaft and means reciprocated thereby toward which all of said actuating means are urged, a manually releasable latch arranged adjacent each of said actuating means normally engaging and holding each of said actuating means against the action of said resilient means and control means for starting and stopping operation of said power-actuated means, said control means comprising a control element actuated by and upon the release of any latch to start operation of said power-actuated means and a second control element actuated by the power-actuated means to stop operation thereof after any actuating means released by its latch has been again reengaged thereby.

Y BERTRAM A. SCHWARZ.

JAMES G. FUNK.

Patent 2,296,06.

CERTIFICATE CE CORRECTION. ,Y

September l5"',`19l; 2. BERTRAM A. SCHWARZ, yET' AL. f

- It f s hereby certified that error eppers in tbe print-ed specification of the above numbered patent requiring Correton as follows Page first Column, line 8, for "conductor"y reed --conduetors-; page 5, first eolnmn, line LIC, Claim 6, for "on seid @actuating means by to stress; and that-the salici.Lettersl Patent should be readwitn `this correction therein that the same ma;Yr conform tothe record of the case'in' the Patent Office.-

signed and sealed this 5th clay` of January, A. `I 19M.

- l Acting Commissioner of Patents.

" read --actuatngmeansl 4 

